Power sourcing equipment and energy saving method for power over ethernet

ABSTRACT

Power sourcing equipment (PSE) and an energy saving method for Power over Ethernet are provided. The PSE includes: a low-power detection component, configured to: detect a power supply port when being connected to the power supply port; and send a first instruction when the power supply port is connected to a valid powered device PD, to instruct a control switch to connect a PSE chip and the power supply port and disconnect the low-power detection component from the power supply port, and instruct a power switch to connect the PSE chip and a power supply; the control switch, configured to: according to the first instruction, connect the PSE chip and the power supply port, and disconnect the low-power detection component from the power supply port; and the power switch, configured to connect the PSE chip to the power supply port according to the first instruction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2018/076740, filed on Feb. 13, 2018, which claims priority toChinese Patent Application No. 201710750171.X, filed on Aug. 28, 2017.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the communications field, and inparticular, to power sourcing equipment and an energy saving method forPower over Ethernet.

BACKGROUND

Power over Ethernet (PoE) includes power sourcing equipment (PSE) and apowered device (PD). The PoE is a wired power over Ethernet technology.The PoE allows data and power to be coupled and transmitted to thepowered device through a network cable, or may allow data and power tobe separated and transmitted to the powered device through a networkcable.

In 2003, the Institute of Electrical and Electronic Engineers (IEEE)released the PoE standard IEEE 802.3af, and the PSE can provide the PDwith 15.4 W power. In 2009, the high-power PoE standard IEEE 802.3at wasreleased, and the PSE can provide the PD with 30 W power. Currently, thePoE standard is still evolving, and is to cover a 90 W power range.

As a growing quantity of PoE devices are popularized and applied, apower loss of the PD is increasingly concerned.

SUMMARY

This application provides power sourcing equipment and an energy savingmethod for Power over Ethernet, to reduce a power loss of the powersourcing equipment and avoid a resource waste.

According to a first aspect, power sourcing equipment is provided, thepower sourcing equipment includes a power supply port, a power sourcingequipment PSE chip, a low-power detection component, a control switch,and a power switch; and the power supply port is connected to thecontrol switch, the PSE chip and the low-power detection component areseparately connected to the control switch, and the PSE chip isconnected to the power switch;

the low-power detection component is configured to: detect the powersupply port when being connected to the power supply port; and send afirst instruction when the power supply port is connected to a valid PD,where the first instruction is used to instruct the control switch toconnect the PSE chip and the power supply port and disconnect thelow-power detection component from the power supply port, and instructthe power switch to connect the PSE chip and a power supply;

the control switch is configured to: according to the first instruction,connect the PSE chip and the power supply port, and disconnect thelow-power detection component from the power supply port; and

the power switch is configured to connect the PSE chip to the powersupply according to the first instruction.

In the foregoing technical solution, when the low-power detectioncomponent detects that the power supply port is connected to a valid PD,the PSE chip is connected to the power supply port, and the low-powerdetection component is disconnected from the power supply port, and thepower switch is instructed to connect the PSE chip and the power supply.In this way, the power supply of the PSE chip is not always connected,so that a power loss can be reduced and a resource waste can be avoided.

In one embodiment, when the PSE chip is connected to the power supplyport, and the PSE chip is connected to the power supply, the PSE chip isconfigured to send a status notification to the low-power detectioncomponent when detecting that the power supply port is in a non-powersupplied state, where the status notification is used to instruct thelow-power detection component to send a second instruction, and thesecond instruction is used to instruct the control switch to disconnectthe PSE chip from the power supply port and connect the low-powerdetection component and the power supply port, and instruct the powerswitch to disconnect the PSE chip from the power supply;

the control switch is further configured to: according to the secondinstruction, disconnect the PSE chip from the power supply port, andconnect the low-power detection component and the power supply port; and

the power switch is further configured to disconnect the PSE chip fromthe power supply according to the second instruction.

In the foregoing technical solution, when the power supply port is inthe non-power supplied state, it indicates that no power needs to besupplied to the PSE chip. The PSE chip can be disconnected from thepower supply to reduce a power loss.

In one embodiment, when the PSE chip is connected to the power supplyport, and the PSE chip is connected to the power supply, the PSE chip isspecifically configured to detect the power supply port, and output anormal supply voltage when a detection result of the power supply portis that the power supply port is connected to a valid PD.

In the foregoing technical solution, to reduce a power loss, the normalsupply voltage is output only when the detection result of the powersupply port is that the power supply port is connected to a valid PD.

In one embodiment, when the PSE chip is connected to the power supplyport, and the PSE chip is connected to the power supply, the PSE chip isspecifically configured to directly output a normal supply voltagethrough the power supply port.

In the foregoing technical solution, the PSE chip can directly output anormal supply voltage through the power supply port to supply power tothe PD in a timely manner.

In one embodiment, an operating voltage of the low-power detectioncomponent is greater than or equal to 10 volts.

In the foregoing technical solution, to detect that the power supplyport is connected to the valid PD, the operating voltage of thelow-power detection component needs to be greater than or equal to 10volts.

In one embodiment, the low-power detection component is located in thePSE chip of the power sourcing equipment.

In the foregoing technical solution, the low-power detection componentis located in the PSE chip, so that the PSE chip is highly integrated.This avoids external interference.

According to a second aspect, an energy saving method for Power overEthernet is provided, and the method is applied to power sourcingequipment that includes a power supply port, a low-power detectioncomponent, and a power sourcing equipment PSE chip, and includes:

detecting, by the low-power detection component, whether the powersupply port is connected to a valid powered device PD, where the powersupply port is connected to the low-power detection component, the powersupply port is disconnected from the PSE chip, and the PSE chip isdisconnected from a power supply; and

when the power supply port is detected as being connected to a valid PD,connecting the PSE chip and the power supply port, disconnecting thelow-power detection component from the power supply port, and connectingthe PSE chip and the power supply.

According to the energy saving method for Power over Ethernet providedin this application, the PSE chip is disconnected from the power supply,the low-power detection component operating at a low voltage detectswhether the power supply port is connected to a valid PD, and after thepower supply port is detected as being connected to a valid PD, the PSEchip is connected to the power supply. This can prevent the power supplyfrom continuously outputting power before the power sourcing equipmentis connected to the valid PD, thereby reducing power consumption of thepower sourcing equipment.

In one embodiment, the method further includes:

when the power supply port is not connected to a valid PD, keeping thepower supply port connected to the low-power detection component, thepower supply port disconnected from the PSE chip, and the PSE chipdisconnected from the power supply, and continuing, by the low-powerdetection component, to detect the power supply port.

In one embodiment, after the connecting the PSE chip and the powersupply port, disconnecting the low-power detection component from thepower supply port, and connecting the PSE chip and the power supply, themethod further includes:

if the PSE chip detects that the PD connected to the power supply portis in a non-power supplied state, disconnecting the PSE chip from thepower supply, disconnecting the PSE chip from the power supply port, andconnecting the low-power detection component and the power supply port,so that the low-power detection component detects the power supply port.

In one embodiment, after the connecting the PSE chip and the powersupply port, disconnecting the low-power detection component from thepower supply port, and connecting the PSE chip and the power supply, themethod further includes:

detecting, by the PSE chip, the power supply port, and outputting anormal supply voltage when a detection result of the power supply portis that the power supply port is connected to a valid PD; or

directly outputting, by the PSE chip, the normal supply voltage throughthe power supply port.

According to a third aspect, a computer readable storage medium isprovided. The computer readable storage medium stores an instruction.When running on a computer, the instruction enables the computer toperform the method according to the second aspect.

According to a fourth aspect, a computer program product that includesan instruction is provided. When running on a computer, the computerprogram product enables the computer to perform the methods according tothe foregoing aspects.

According to a fifth aspect, a power supply system is provided andincludes a powered device and the power sourcing equipment according tothe first aspect.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic structural diagram of power sourcing equipmentaccording to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of power sourcing equipmentaccording to another embodiment of the present invention;

FIG. 3 is a schematic structural diagram of power sourcing equipmentaccording to still another embodiment of the present invention; and

FIG. 4 is a schematic flowchart of an energy saving method for Powerover Ethernet according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

In the embodiments of the present invention, when a power supply port isdetected as being connected to a valid PD, a PSE chip is connected tothe power supply port, a low-power detection component is disconnectedfrom the power supply port, and a power supply of the PSE chip isconnected. The power supply of the PSE chip is not always connected, andthe power supply of the PSE chip is connected only when a specificcondition is met, so that a power loss can be reduced and a resourcewaste can be avoided.

PSE specifically includes a power supply, a PSE chip, and a power supplyport. The power supply provides a voltage for the PSE chip, and controlsa voltage of the PSE chip by using a switch inside the PSE chip. The PSEchip continuously detects a PD by using the power supply port. Whendetecting a valid PD, the PSE chip outputs a voltage to the power supplyport to supply power to the PD.

The voltage provided by the power supply for the PSE chip is anoperating voltage stipulated in a standard, namely, a normal supplyvoltage, for example, 48 volts (V). The switch inside the PSE chip maybe specifically a metal-oxide semiconductor field-effect transistor(MOSFET).

Even if the power supply port is idle, that is, even if the power supplyport is not connected to a valid PD, the power supply always provides a48 V voltage for the power supply port. Apparently, power isunnecessarily lost and resources are wasted.

FIG. 1 is a schematic structural diagram of power sourcing equipmentaccording to an embodiment of the present invention. The power sourcingequipment specifically includes a power supply port 101, a PSE chip 102,a low-power detection component 103, a control switch 104, and a powerswitch 105. The power supply port 101 is connected to the control switch104, The PSE chip 102 and the low-power detection component 103 areseparately connected to the control switch 104, and the PSE chip 102 isconnected to the power switch 105. The PSE chip 102 performs relatedfunctions in a manner defined in a standard.

The low-power detection component 103 is configured to: when beingconnected to the power supply port 101, detect whether the power supplyport 101 is connected to a valid PD. The low-power detection component103 performs detection when operating at a low voltage.

The low voltage at which the low-power detection component 103 operatesand a supply voltage output to the power supply port are independent ofeach other, but both come from a power management system of the powersourcing equipment. The power management system outputs a voltage basedon a requirement of each component in the power sourcing equipment. Inthis embodiment of the present invention, a part that is in the powermanagement system of the power sourcing equipment and that suppliespower to the power supply port is referred to as a power supply.

A specific process of detecting the power supply port is as follows: Twodifferent detection voltages are output through the power supply port101, and an interval between the two different detection voltages isgreater than or equal to 1 V. Then impedance is calculated based onvalues of two different detected currents and the two differentdetection voltages. If the impedance falls within a preset range, thepower supply port 101 is determined as being connected to a valid PD. Ifthe impedance goes beyond the preset range, the power supply port 101 isdetermined as not being connected to a valid PD.

When all power supply ports are idle, that is, none of the power supplyports is connected to a valid PD, the power supply port 101 keepsconnected to the low-power detection component 103, the power supplyport 101 keeps disconnected from the PSE chip 102, the PSE chip 102keeps disconnected from the power supply, and the low-power detectioncomponent 103 continues to detect the power supply port 101.

When detecting that the power supply port 101 is connected to a validPD, the low-power detection component 103 sends a first instruction. Thefirst instruction is used to connect the PSE chip 102 to the powersupply, connect the PSE chip 102 and the power supply port 101, anddisconnect the low-power detection component 103 from the power supplyport 101.

Specifically, the control switch 104 is configured to: according to thefirst instruction, connect the PSE chip 102 and the power supply port101, and disconnect the low-power detection component 103 from the powersupply port 101.

Specifically, the power switch 105 is configured to connect the PSE chip102 to the power supply according to the first instruction.

The low-power detection component 103 can detect the power supply port101 when operating at a low voltage.

In this embodiment of the present invention, if the low-power detectioncomponent 103 detects that the power supply port 101 is connected to avalid PD, the power supply of the PSE chip 102 is connected. In thisway, a supply voltage of the PSE chip 102 is not always connected, sothat a power loss can be reduced and a resource waste can be avoided.

In one embodiment, when the PSE chip 102 is connected to the powersupply port 101, and the PSE chip 102 is connected to the power supply,the PSE chip 102 sends a status notification to the low-power detectioncomponent 103 when detecting that the power supply port 101 is in anon-power supplied state. The status notification is used to instructthe low-power detection component 103 to send a second instruction. Thesecond instruction is used to instruct the control switch 104 todisconnect the PSE chip 102 from the power supply port 101, and connectthe low-power detection component 103 and the power supply port 101, andinstruct the power switch 105 to disconnect the PSE chip 102 from thepower supply.

The control switch 104 is configured to: according to the secondinstruction, disconnect the PSE chip 102 from the power supply port 101,and connect the low-power detection component 103 and the power supplyport 101.

The power switch 105 is configured to disconnect the PSE chip 102 fromthe power supply according to the second instruction.

In the foregoing technical solution, if the PD connected to the powersupply port 101 is in the non-power supplied state, it indicates that nopower supply needs to be provided for the PD. The power supply can bedisconnected to reduce a power loss.

In one embodiment, when the PSE chip 102 is connected to the powersupply port 101, and the PSE chip 102 is connected to the power supply,the PSE chip 102 may detect the power supply port 101, and output anormal supply voltage when a detection result of the power supply port101 is that the power supply port is connected to a valid PD.

The PSE chip 102 outputs a low voltage (a detection voltage, a gradingvoltage, a power-on voltage, or the like) or a normal supply voltage tothe power supply port 101. The power supply port 101 outputs a lowvoltage when the PSE chip 102 detects no valid PD, and outputs thenormal supply voltage when the PSE chip 102 detects a valid PD.

The detection of the power supply port 101 is as follows: The PSE chip102 sends a detection voltage to a PD to detect common-mode resistancein the PD.

In one embodiment, after detecting the PD, the PSE chip 102 may performphysical layer grading on the PD. Specifically, the PSE chip 102 mayapply a voltage of 15 V to 20 V to the PD, and determine a grade of thePD by testing a magnitude of a current.

After the grading is completed if the grading is performed, or after thevalid PD is detected if no grading is performed, the PSE starts tosupply power to the PD at a low voltage in a start-up period whoseduration is configurable.

In the technical solution, to ensure validity of the PD connected to thepower supply port 101, the PSE chip 102 may detect the power supply port101 again, and supply power, that is, output the normal supply voltagewhen a detection result is that the power supply port is connected to avalid PD.

In one embodiment, to quickly supply power to the PD, when the PSE chip102 is connected to the power supply port 101, and the PSE chip 102 isconnected to the power supply, the PSE chip 102 may directly output anormal supply voltage through the power supply port 101 withoutdetecting the power supply port 101 again after the power supply isconnected.

In one embodiment, an operating voltage of the low-power detectioncomponent 103 is greater than or equal to 10 V. In this case, it iseasier to detect the power supply port 101.

In one embodiment, the low-power detection component 103 may be in thePSE chip 102.

FIG. 2 is a schematic structural diagram of power sourcing equipmentaccording to another embodiment of the present invention. A power supply204 supplies power to a PSE chip 201 by using a power switch 205. ThePSE chip 201 and a low-power detection component 202 are separatelyconnected to a control switch 203.

Specifically, the low-power detection component 202 detects whether apower supply port 206 is connected to a valid PD. If the power supplyport 206 is not connected to a valid PD, the power supply port 206 keepsconnected to the low-power detection component 202, the power supplyport 206 keeps disconnected from the PSE chip 201, the PSE chip 201keeps disconnected from the power supply 204, and the low-powerdetection component 202 continues to detect the power supply port 206.If the power supply port 206 is connected to a valid PD, the powersupply of the PSE chip 201 is connected through the power switch 205,the PSE chip 201 is connected to the power supply port 206, and thelow-power detection component 202 is disconnected from the power supplyport 206.

The low-power detection component 202 is located outside the PSE chip201, and the control switch 203 and the power switch 205 are alsolocated outside the PSE chip 201. In other words, a structure of the PSEchip does not change. The low-power detection component 202, the controlswitch 203, and the power switch 205 are added outside the PSE chip 201to control an output voltage of the power supply port 206. Therefore,the output voltage of the power supply port 206 can be controlled on thebasis of the PSE chip 201 without a need to alter the PSE chip 201.

In addition, the power sourcing equipment may further include aprocessor and a memory, and the processor, the memory, and the powersupply port 206 may be connected to each other through a bus.

The processor may be one or more central processing units (CPU). Whenthe processor is one CPU, the CPU may be a single-core CPU, or may be amulti-core CPU.

The memory may be but is not limited to one or more of a random accessmemory (RAM), a read-only memory (ROM), an erasable programmable readonly memory (EPROM), a compact disc read-only memory (CD-ROM), and ahard disk. The memory may be further configured to store program code.

In one embodiment, a low-power detection component may be in a PSE chip.FIG. 3 is a schematic structural diagram of power sourcing equipmentaccording to still another embodiment of the present invention.

A power supply 304 is connected to a PSE chip 301 through a power switch305. The PSE chip 301 and a low-power detection component 302 areseparately connected to a power supply port 306 through a control switch303.

The low-power detection component 302 is located inside the PSE chip301. The low-power detection component 302 and the PSE chip 301 areseparately connected to the power supply port 306 through differentpins.

Specifically, the low-power detection component 302 detects the powersupply port 306. If the power supply port 306 is not connected to avalid PD, the power supply port 306 keeps connected to the low-powerdetection component 302, the power supply port 306 keeps disconnectedfrom the PSE chip 301, the PSE chip 301 keeps disconnected from thepower supply 304, and the low-power detection component 302 continues todetect the power supply port 306.

The low-power detection component 302 detects the power supply port 306.If the power supply port 306 is connected to a valid PD, the powersupply of the PSE chip 301 is connected by using the power switch 305,the PSE chip 301 is connected to the power supply port 306, and thelow-power detection component 302 is disconnected from the power supplyport 306.

The low-power detection component 302 is located inside the PSE chip301, so that the PSE chip 301 is highly integrated. This avoids externalinterference, and improves reliability of detecting whether the powersupply port 306 is connected to a valid PD.

In addition, the power sourcing equipment may further include aprocessor and a memory, and the processor, the memory, and the powersupply port 306 are connected to each other through a bus.

The processor may be one or more CPUs. When the processor is one CPU,the CPU may be a single-core CPU, or may be a multi-core CPU.

The memory may be but is not limited to one or more of a RAM, a ROM, anEPROM, a CD-ROM, and a hard disk. The memory is configured to storeprogram code.

FIG. 4 is a schematic flowchart of an energy saving method for Powerover Ethernet according to an embodiment of the present invention. Themethod is applied to the power sourcing equipment shown in FIG. 1 andspecifically includes the following operations.

S401. A low-power detection component detects a power supply port.

First, the power supply port is connected to the low-power detectioncomponent, the power supply port is disconnected from a PSE chip, thePSE chip is disconnected from a power supply, and the low-powerdetection component may detect, at a low voltage, whether the powersupply port is connected to a valid PD.

Specifically, two different detection voltages are output through thepower supply port, and an interval between the two different detectionvoltages is greater than or equal to 1 V. Then impedance is calculatedbased on values of two different detected currents and the two differentdetection voltages. If the impedance falls within a preset range, thepower supply port is determined as being connected to a valid PD, andS403 is performed. If the impedance goes beyond the preset range, thepower supply port is determined as not being connected to a valid PD,and S402 is performed.

S402. When none of power supply ports is connected to a valid PD, thepower supply port keeps connected to the low-power detection component,the power supply port keeps disconnected from a PSE chip, the PSE chipkeeps disconnected from a power supply, and the low-power detectioncomponent continues to detect the power supply port.

When none of the power supply ports is connected to a valid PD, itindicates that no power needs to be supplied to the PSE chip, and onlythe low-power detection component needs to keep connected to the powersupply port to detect whether the power supply port is connected to avalid PD.

S403. When the power supply port is detected as being connected to avalid PD, a control switch connects a PSE chip and the power supplyport, and disconnects the low-power detection component from the powersupply port, and a power switch connects the PSE chip and a powersupply.

When the power supply port is detected as being connected to a valid PD,it indicates that power needs to be supplied to the PSE chip. In thiscase, the PSE chip needs to be connected to the power supply port, thelow-power detection component needs to be disconnected from the powersupply port, and the power supply of the PSE chip needs to be connected.

In this embodiment of the present invention, when the power supply portis detected as being connected to a valid PD, the power supply of thePSE chip is connected. In this way, a supply voltage is not alwaysconnected, so that a power loss can be reduced and a resource waste canbe avoided.

In one embodiment, when the PSE chip is connected to the power supply,and the PSE chip detects that the PD connected to the power supply portis in a non-power supplied state, it indicates that no power supplyneeds to be provided for the PD. In this case, the PSE chip isdisconnected from the power supply, the PSE chip is disconnected fromthe power supply port, and the low-power detection component isconnected to the power supply port, so that the low-power detectioncomponent detects the power supply port.

In the foregoing technical solution, if the PD connected to the powersupply port is in the non-power supplied state, it indicates that nopower needs to be supplied to the PD. The power supply of the PSE chipcan be disconnected to reduce a power loss.

In one embodiment, to ensure validity of the PD connected to the powersupply port, the PSE chip detects the power supply port again, andoutputs a normal supply voltage through the power supply port when adetection result of the power supply port is that the power supply portis connected to a valid PD.

Alternatively, the PSE chip directly outputs a normal supply voltagethrough the power supply port to quickly supply power to the PD.

In one embodiment, an operating voltage of the low-power detectioncomponent may be greater than or equal to 10 V. In this case, it iseasier to detect the power supply port.

The parts in this specification are all described in a progressivemanner. For same or similar parts in the embodiments, refer to theseembodiments. Each embodiment focuses on a difference from otherembodiments. Especially, the method embodiment is basically similar tothe apparatus embodiments, and therefore is described in brief. Forrelated parts, refer to descriptions in the apparatus embodiments.

What is claimed is:
 1. A power sourcing equipment (PSE), comprising: apower supply port; a PSE chip; a power switch, wherein the power switchis connected to the PSE chip, and is configured to connect the PSE chipto a power supply; a low-power detection component; a control switch,wherein the control switch is connected to the PSE chip, the low-powerdetection component, and the power supply port; and wherein thelow-power detection component is configured to: detect the power supplyport when the low power detection component is being connected to thepower supply port, and send a first instruction to the control switch inresponse to detecting that the power supply port is connected to a validpowered device, wherein the first instruction instructs the controlswitch to connect the PSE chip and the power supply port and disconnectthe low-power detection component from the power supply port, andinstructs the power switch to connect the PSE chip and the power supply;wherein the PSE chip is configured to: send a status notification to thelow-power detection component when detecting that the power supply portis in a non-power supplied state, wherein the status notificationinstructs the low-power detection component to send a second instructionto instruct the control switch to disconnect the PSE chip from the powersupply port and connect the low-power detection component to the powersupply port, and to instruct the power switch to disconnect the PSE chipfrom the power supply; wherein the control switch is configured to:disconnect, according to the second instruction, the PSE chip from thepower supply port, and connect the low-power detection component and thepower supply port; wherein the power switch is configured to disconnectthe PSE chip from the power supply according to the second instruction.2. The power sourcing equipment according to claim 1, wherein when thePSE chip is connected to the power supply port and the power supply, thePSE chip is configured to detect the power supply port, and output anormal supply voltage in response to detecting that the power supplyport is connected to the valid powered device.
 3. The power sourcingequipment according to claim 1, wherein when the PSE chip is connectedto the power supply port and the power supply, the PSE chip isconfigured to directly output a normal supply voltage through the powersupply port.
 4. The power sourcing equipment according to claim 1,wherein an operating voltage of the low-power detection component isgreater than or equal to 10 volts.
 5. The power sourcing equipmentaccording to claim 1, wherein the low-power detection component islocated in the PSE chip.
 6. A method for power sourcing, the methodcomprising: detecting, by a low-power detection component of a powersourcing equipment (PSE), that a power supply port of the PSE isconnected to a valid powered device, wherein the PSE further includes aPSE chip, a power switch, and a control switch, wherein the power switchis connected to the PSE chip and is configured to connect the PSE chipto a power supply, wherein the control switch is connected to thelow-power detection component, the PSE chip, and the power supply port;in response to detecting the power supply port is connected to the validpowered device, sending, by the low-power detection component of thePSE, a first instruction to the control switch, wherein the firstinstruction instructs the control switch to connect the PSE chip and thepower supply port, and disconnect the low-power detection component fromthe power supply port, and instructs the power switch to connect the PSEchip and the power supply; sending, by the PSE chip of the PSE, a statusnotification to the low-power detection component when detecting thatthe power supply port is in a non-power supplied state, wherein thestatus notification instructs the low-power detection component to senda second instruction to instruct the control switch to disconnect thePSE chip from the power supply port and connect the low-power detectioncomponent to the power supply port, and to instruct the power switch todisconnect the PSE chip from the power supply; disconnecting, by thecontrol switch of the PSE according to the second instruction, the PSEchip from the power supply port, and connect the low-power detectioncomponent and the power supply port; and disconnecting the PSE chip ofthe PSE, from the power supply according to the second instruction. 7.The method according to claim 6, further comprising: detecting that thepower supply port is disconnected from the valid powered device, keepingthe power supply port connected to the low-power detection component,the power supply port disconnected from the PSE chip, and the PSE chipdisconnected from the power supply, and continuing, by the low-powerdetection component, to detect the power supply port.
 8. The methodaccording to claim 6, further comprising: after the PSE chip and thepower supply port are connected, disconnecting the low-power detectioncomponent from the power supply port, and connecting the PSE chip andthe power supply.
 9. The method according to claim 6, furthercomprising: detecting, by the PSE chip, the power supply port, andoutputting a normal supply voltage in response to detecting that thepower supply port is connected to the valid powered device, or directlyoutputting, by the PSE chip, a normal supply voltage through the powersupply port.
 10. The method according to claim 6, wherein an operatingvoltage of the low-power detection component is greater than or equal to10 volts.
 11. The method according to claim 6, wherein the low-powerdetection component is located in the PSE chip.
 12. A power supplysystem, comprising: a powered device; and a power sourcing equipment(PSE) including: a power supply port, a PSE chip, a low-power detectioncomponent, a control switch, and a power switch, wherein the powerswitch is connected to the PSE chip and is configured to connect the PSEchip to a power supply, wherein the control switch is connected to thePSE chip, the low-power detection component, and the power supply port;wherein the low-power detection component is configured to: detect thepower supply port when the low power detection component is beingconnected to the power supply port, and send a first instruction to thecontrol switch in response to detecting that the power supply port isconnected to the powered device, wherein the first instruction instructsthe control switch to connect the PSE chip and the power supply port anddisconnect the low-power detection component from the power supply port,and instructs the power switch to connect the PSE chip and the powersupply; wherein the PSE chip is configured to: send a statusnotification to the low-power detection component when detecting thatthe power supply port is in a non-power supplied state, wherein thestatus notification instructs the low-power detection component to senda second instruction to instruct the control switch to disconnect thePSE chip from the power supply port and connect the low-power detectioncomponent to the power supply port, and to instruct the power switch todisconnect the PSE chip from the power supply; wherein the controlswitch is configured to: disconnect, according to the secondinstruction, the PSE chip from the power supply port, and connect thelow-power detection component and the power supply port; wherein thepower switch is configured to disconnect the PSE chip from the powersupply according to the second instruction.
 13. The power supply systemaccording to claim 12, wherein when the PSE chip is connected to thepower supply port and the power supply, the PSE chip is configured todetect the power supply port, and output a normal supply voltage inresponse to detecting that the power supply port is connected thepowered device.
 14. The power supply system according to claim 12,wherein when the PSE chip is connected to the power supply port and thepower supply, the PSE chip is configured to directly output a normalsupply voltage through the power supply port.
 15. The power supplysystem according to claim 12, wherein an operating voltage of thelow-power detection component is greater than or equal to 10 volts. 16.The power supply system according to claim 12, wherein the low-powerdetection component is located in the PSE chip.